Apparatus for molding an article from a fusible synthetic resin

Abstract

An apparatus for reflow smoothing a molded article made by first heating a face of a mold at a first station, then applying a fusible synthetic resin to the heated face and thereby melting the resin into a continuous coating covering the heated mold face at a second station spaced angularly from the first station, and cooling the coating and mold at the second station until the coating hardens. To reflow smooth the article, the surface of the cooled coating is then smoothed by confining the mold and hardened coating in a substantially closed chamber at the second station and reheating the confined coating until its surface flows. Thereafter the coating is cooled again at a third station angularly spaced from and downstream of the second station until it hardens and the hardened covering is stripped from the mold at a fourth station angularly spaced downstream of the third station and upstream of the first station.

We claim: 
     
       1. An apparatus for making a molded article from a fusible synthetic resin, the apparatus comprising: a mold having a front face of a shape corresponding to the article to be made and a back face;   transport means for pivoting the mold in an angular transport direction about a central upright axis through a heating station, a coating station offset angularly downstream therefrom, a cooling station offset angularly downstream therefrom, and a demolding station offset angularly downstream from the cooling station and angularly upstream from the heating station, the stations being generally angularly equispaced about the axis;   means at the heating station for heating the front face of the mold;   means at the coating station for applying a fusible synthetic resin to the heated front face and thereby melting the resin into a continuous coating covering the mold front face;   means at the coating station for cooling the coating and mold until the coating hardens;   means at the coating station including a chamber closable around the mold and coating for confining the mold;   means in the chamber for reheating the coating until its surface flows;   means at the cooling station for recooling the coating and mold until the coating hardens again; and   means at the demolding station for stripping the hardened covering from the mold.   
     
     
       2. The apparatus defined in claim 1 wherein the heating means in the chamber includes a plurality of radiant heat sources directed at the front mold face and the coating thereon. 
     
     
       3. The apparatus defined in claim 2 wherein the heating means in the chamber includes a blower in the chamber for recirculating gases therein over the coating. 
     
     
       4. The apparatus defined in claim 2, further comprising means for rotating the chamber and mold and coating therein about two relatively transverse axes during the reheating step. 
     
     
       5. The apparatus defined in claim 2, further comprising means for introducing a clean gas into the chamber during the reheating step. 
     
     
       6. The apparatus defined in claim 2, further comprising means for withdrawing gases from the chamber during the reheating step. 
     
     
       7. The apparatus defined in claim 2, further comprising means for introducing an inert gas into the chamber during the reheating step. 
     
     
       8. The apparatus defined in claim 2, further comprising means for introducing a cool gas into the chamber during the reheating step. 
     
     
       9. The apparatus defined in claim 2, further comprising means for withdrawing gases from the chamber during the reheating step and for processing and cleaning the withdrawn gases.